The field of cap and tube assemblies which carry medicines, vitamins and the like, has become of major importance and interest in the pharmaceutical industry. It is a growing need that container assemblies be difficult for children to open, particularly accidentally. Also, increased interest is being shown in cap and tube assemblies which cannot be opened by happenstance but which require a specific and positive step to be taken in order to have access to the contents. This is particularly true when medicines, vitamins and topical treatments such as eye drops are contained in such tubes.
It is also important that it be easy and certain to determine if there has been access to the contents. This is normally referred to as a "tamper evident" feature, although in many cases the primary function is to provide an inspection means which verifies the integrity of the contents. Most concern is not for tampering, which can be serious if not deadly but which is very rare in actuality. At best, tamper evidence means that the one attempting to tamper has not done that which is obvious, such as breaking a visible seal or the like.
More common as a concern is the need to be sure that the contents are pure and have not been contaminated by the environment. In many tube assemblies, the outside environment can and does come in contact with the discharge end of the tube and also with the part of the tube out of which the sterile contents will flow. No matter how sterile the container, if it pours over contaminated surfaces the contents will also be contaminated.
In prior art devices, tube assembly designs have been proposed which include a three piece construction where a tube body contains a plug attached to a portion of the main body of the tube. The wall of the tube has been weakened sufficiently to permit the plug to be torn from the tube. A cap portion is designed so that one end might be fitted over the tube having the plug, thereby protecting the plug and tube. The other end is then designed to interact with the plug in a twisting manner to remove the plug by rupturing the thin wall of the tube to which the plug is attached. This design has not been effective, however, because of the additional concern caused by the existence of the plug and the need for safe and reliable disposal of the plug.
In U.S. Pat. No. 4,867,326, a child-resistant cap and tube assembly is shown which has a high reliability in pass/fail inspection opportunities. This design permits easy inspection of unit dose sterile medicaments.
This prior device has a tube which has one end portion terminating in an axially centered first opened surface at the outer perimeter of the end portion. Recessed below the surface of the end portion is a thin wall which seals the tube. The tube has a second surface, called a surface of interference, which operates to interfere with axial movement on the end portion. The cap has a resistance surface which engages the end to locate the cap at a first position where the thin wall portion on the tube is protected. Movement overcoming the restraining efforts of the two surfaces causes a piercer to move to then puncture the thin wall and provide access to the contents.
The prior device in U.S. Pat. No. 4,867,326 has been highly effective in keeping children and others from inadvertently opening the container and causing loss or damage to the contents. It is also suitable for a pass/fail inspection step as the thin wall is clearly visible when the cap is removed. The condition of the thin wall is easily determined visually.
In the prior system, axial activation force was all that was needed to overcome the engagement between the resistance surface and the surface of interference. Once this is overcome for whatever reason, the piercer moves to the second position as described in that patent and the thin wall seal which has been protecting the contents is pierced. That is desirable only when the user makes that decision and not merely because the force has been overcome inadvertently.
It is therefore an object of this invention to provide a child-resistant tube and cap assembly that requires more than axial force to provide access to the contents.
In any system including those described above, when the piercing agent enters the container from the outside, there is always the potential that the piercer will bring contamination with it. Even in the systems described above, the sterile conditions are maintained nicely only when the cap is never removed from the tube nozzle until after it is intentionally activated. Under many circumstances, this is fine, but when visual inspection of the thin wall membrane is desired, such as when there is suspicion that the tube assembly has been in the hands of children or other unauthorized persons, it is comforting to inspect the thin wall visually. When the cap is removed to do this step, the possibility for contamination exists.
Accordingly, it is an object of this invention to provide a device which is capable of providing not only child-resistance but also a quick visual warning or sign that the device has in fact been opened.
It is another object of this invention to provide an activation system which permits visual inspection without the possibility that the piercing member will be contaminated.
It is primary object of this invention to provide a simple and effective design for permitting sanitary and sterile access to the contents of a tube assembly without the possibility of the piercing agent entering into the tube after assembly.
Other objects will appear hereinafter.